let oneDigitPrimes = new Set([3, 5, 2, 7]);
console.log(oneDigitPrimes.has(2)); // true
console.log(oneDigitPrimes.has(3)); // true
console.log(oneDigitPrimes.has(4)); // false
console.log(oneDigitPrimes.has(5)); // true
for (const p of oneDigitPrimes) {
  console.log(p); // 3 5 2 7
}
console.log(`${[...oneDigitPrimes]}`); // 3,5,2,7
